الفهرس 
DUCTILE FRAME JOINTSOnly 14 pages are availabe for public view
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Abstract
Reinforced concrete joints and comers have been shown to be potentially the weakest
elements in ductile reinforced concrete frames. Therefore, the joint region should be designed in a
manner that will assure the required load bearing capacity, elastic and inelastic rotations, crack
widths, and acceptable frame deformations. Different types of fuilure may be obtained in frame
joints. The failure inside the joint core is the most critical mode of fililure because it may lead to
sudden frame fuilures.
The effect of transverse beams, the contribution of slabs to stiffness and strength of joints,
and the anchorage of bars inside the joints have been investigated in a number of recent researches.
Recently, ACI-ASCE Committee 352, ”The Committee of Joints and Connections in Monolithic
Concrete Structures”, demonstrated the areas needing research in frame joints as follows:
connections with beams wider than columns, high strength transverse reinforcement inside the
joints, concrete shear strength inside the joints, details to reduce steel congestion inside the joint,
effective joint width, joints with fiber reinforcement or high strength concrete, joints with eccentric
beams. The first five items were studied in the present research work.
An experimental program was conducted in the present research work by testing six
reinforced concrete frames with different joint details, different joint stirrup contents and types, and
different joint configurations in order to study the effect of these items on the frames general
deformational behaviour, the load carrying capacities, the cracking behaviour, and the failure
modes.
A non-linear finite element computer program was developed for the analytical study of the
present research work. This program takes into account the material non-linearity for both concrete
and stee~ the tension stiffening of cracked elements, the strain softening, the bond-slip relationship
between steel and concrete, and the confinement effect of stirrups. This developed program was
used to analyse fourteen different models to achieve the obtained experimental results in addition to
investigating the effective joint widths and the concrete shear strengths of the tested joints.
The experimental and the theoretical resuhs of the present research work were combined
together in order to develop recommendations in the field of ductile frame joints. It has been found
out both experimentally and theoretically that joint confinement by transverse and longitudinal joint
reinforcement, adding inclined reinforcing bars, and providing corbels for exterior joints, if
possible, can prove to be useful in transferring the joint behaviour from a brittle behaviour to a
ductile one. The effective joint widths were investigated in the present study with beam widths
smaller or bigger than the columns. Also, formulae were developed for estimating the joint shear
strength with different reinforcement details.